Dr. Stone Vol. 4 (manga)

Imagine waking to a world where every last human has been mysteriously turned to stone...

One fateful day, all of humanity turned to stone. Many millennia later, Taiju frees himself from the petrification and finds himself surrounded by statues. The situation looks grim--until he runs into his science-loving friend Senku! Together they plan to restart civilization with the power of science!

Senku and friends continue their quest to procure a sulfa drug panacea for Ruri, the village shamaness who is gravely ill! The toughest ingredient to obtain is sulfuric acid, the search for which will lead them on a death-defying journey! Meanwhile, the Grand Bout Martial Arts Tournament approaches, with the chief's throne offered as a prize to the winner!